Cell structure - Euk cells Flashcards
What are some examples of Euk cells
All animal and plant cells
Algae
Fungi
What is the difference between an animal and plant cell
Plant cell has a cellulose cell wall and a vacuole and chloroplasts whereas an animal cell doesnt
What are the differences between a plant cell and a fungal cell
A fungal cells cell wall is made from chitlin and they don’t have chloroplasts
What is the function and description of a cell membrane
Made of mainly lipids and proteins
It regulates the movement of substances in and out the cell
It has receptor molecules that allow it to respond to chemicals
What is the description and function of a nucleus
It has a nuclear envelope ( double memb )
This contains pores
It has a nucleolus
The nucleus controls the cells activities
Contains DNA
The pores allow substances such as RNA to move between nucleus and cytoplasm
The nucleolus makes ribosomes
Structure and function of Mitochondria
Oval shaped
Double membrane - the inner memb is folded to form cristae and inside is the matrix which contains enzymes involved in respiration
Mitochondria is the site of respiration and where ATP is produced
Structure and function of chloroplast
Small flattened structure surrounded by double memb and has membranes inside called thylakoids. These are stacked up to form grana which are linked together by lamalle
Structure and function of golgi apparatus
Fluid filled membrane bound flattened sacs that have vesicles on the edge of the sacs
Function of RER
Ribosomes on surface synthesise proteins
● Proteins processed / folded / transported inside rER
● Proteins packaged into vesicles for transport eg. to Golgi apparatus
SER
Synthesises and processes lipids
Describe the function of lysosomes
Release hydrolytic enzymes (lysozymes)
● To break down / hydrolyse pathogens or worn-out cell components
Compare structure of euk and prok
Prok has no nucleus or membrane bound organelles
DNA is circular and shorter
Smaller ribosomes
cell wall has murrain
has plasmids, flagella and capsule sometimes present but in euk no plasmids or capsule but sometimes flagella
Explain why viruses are described as acellular and non-living
Acellular - not made of cells, no cell membrane / cytoplasm / organelles
● Non-living - have no metabolism, cannot independently move / respire / replicate / excrete
Describe the general structure of a virus particle
Capsid
Attachment protein
Compare transmission and snanning microscopes
Tranmission
Electrons pass through specimen and denser parts are darker
2D
High resolution, can see internal structures
can only view dead
thin specimen
Scanning
electrons deflected of surface
3D
can’t see internal structures
can be thick
Describe and explain the principles of cell fractionation and ultracentrifugation as used to separate cell components
Homogenise tissue / use a blender
Place in a cold, isotonic, buffered solution:
Cold to reduce enzyme activity
○ So organelles not broken down / damaged
● Isotonic so water doesn’t move in or out of organelles by osmosis ○ So they don’t burst
● Buffered to keep pH constant
○ So enzymes don’t denature
Filter homogenate
Ultracentrifugation:
Centrifuge homogenate in a tube at a low speed
● Remove pellet of heaviest organelle and respin supernatant
at a higher speed
● Repeat at increasing speeds until separated out, each time the
pellet is made of lighter organelles (nuclei → chloroplasts / mitochondria → lysosomes → ER → ribosomes)
Describe how viruses replicate
Attachment proteins attach to complementary receptors on host cell
2. Inject viral nucleic acid (DNA/RNA) into host cell
3. Infected host cell replicates virus particles:
a. Nucleic acid replicated
b. Cell produces viral protein / capsid / enzymes
c. Virus assembled then released
